Pump problem?

rinaldok

0
Gold Supporter
Sep 16, 2016
136
Peoria, AZ
Hi everyone,

I think my pump may be on its way out. It's a single speed Whisperflo 1HP (1.65) and I've been told by a couple pool pros that the motor is not original, it's been replaced at least once. Currently it's a black AO Smith motor, which I've gathered is pretty standard issue.

The past couple weeks, I've been having issues with pressure being low. My sand filter's pressure can't seem to get above 17-18psi. I've had a couple pool guys out and they say "don't worry about it -- water is flowing fine" but have noted that my pump does sound like it's seen better days (bearings? seals?). Also, the pump runs HOT. One guy burned his hand when reaching to feel for the filter drain plug, pulled his hand back quickly and said "Holy SH$$ that's HOT!!!". I realize the motors generate a good bit of heat, but I guess mine is hotter than what would be considered normal.

While they may say "don't worry about it" -- the engineer in me worries about it, and here's why. Water may be flowing, and 17psi may be an OK pressure in generic circumstances, but it's not a typical behavior of my system. Something is different, and that's what's concerning me.

I moved into this house in early July and became acquainted with the pool and the system. At the time, the Navigator cleaner was having trouble getting around. I began educating myself, and discovered that the filter pressure was around 30psi -- that's when I learned what backwashing is. I backwashed thoroughly for a good 5-6 minutes and the filter pressure dropped to about 18psi and all was great (the cleaner, however, still had its share of problems and after being rebuilt twice by Leslie's I just gave up and bought a Phoenix 2X cleaner which works much better.)

What I found was it that would typically take about 2 weeks for the pressure to get up to around 25-26psi and that's when the cleaner would struggle, and so I was backwashing pretty much every 2 weeks all summer. Clean pressure was around 17-18, I would backwash around 25-26.

A few weeks ago I noticed a strange noise coming from the pump so I investigated and found that the filter was running at 9psi and the pump was struggling. There was some debris in the pump basket but it wasn't totally clogged... but I cleaned it all out and the pressure got up to about 14psi. I was leaving for a week so I had our housesitter keep an eye on it... she said it stayed like that all week whenever it was running.

In the past few weeks I've had a couple guys out to look at it, like I've said. One of them helped me get the cover off the sand filter (I tried once and it was stuck on so bad I broke the plastic wrench thingie...) and he replaced the O-ring (which I had on hand, I could just never get the cover off!) which resolved a small seepage leak from the filter top. He dug his hand into the sand and said the sand looks fine, in his opinion no need to replace it or anything. Ok, great.

Last week I took the pump motor off the housing (second time I've done this) and cleaned every speck of debris out of the impeller and cleaned some of the grime off the surfaces. I lubed the O-ring and reassembled. No leaks, which is fine, but I still cannot get the pressure to get above 17-18psi.

Water IS flowing. I do get water coming into the pump, it primes and there's no air bubbles or cavitation. The suction cleaner works, the skimmer is moving water, and I get flow out of the returns. It's just not "how it usually is" and I'm not sure what's up. I let the filter go for a good 4 weeks without a backwash and it never got above 18psi. I have just as much (or more) debris falling in the pool daily now as I did all summer, and the water condition is the same, so the filter should be getting as much or more of a workout, no?

I've noticed that even a small buildup of debris in the pump basket causes the pressure to start to drop. I was just out there and I turned the pump on to check it, the filter was at 16psi. The basket had a small amount of very small leaves in front of the impeller. I cleaned it out, and I'm back to about 17.5psi.

Is the logical conclusion here that the pump is just dying and losing its ability to push water at the same pressure?

I'm sure it's not often people WANT their pressure to get higher in the filter, but to me that would indicate a more normal behavior.

Side note: I have a home warranty but they won't replace the pump unless it's DEAD. And, at that, they'll only cover the cost of a like replacement (which would probably be a rebuilt motor I'm guessing). At best, I'm thinking they might cover $400 or so. I've been looking into VS pumps, and with a 14k-ish gallon pool and no water features (1 skimmer, 1 suction cleaner, 3 return jets... that's it) I know I don't need a monster pump, but I've seen quite a few things saying the "right sized" smaller HP VS pumps aren't a good choice. They're nearly the same price as their full power brothers and they would have to run much higher power to keep up, whereas a larger pump can run at a much lower speed to get the water flow that I need.

Yes/no?

I saw another post on here, because I had the same question, about how I could "encourage" this pump to die so I can replace it. If I had to pay a $800 or so upcharge/delta to get a VS installed and have the warranty cover $400 or whatever amount they'll cover, I think it's a win/win. Their contractor gets work and I get a VS pump and its benefits. I understand the arguments about whether it's ethical or not, but I don't think it's hurting anyone if this pump should suddenly find itself on the losing end of some "random" event that caused its demise. Any suggestions are welcome.

So, to the original question -- is the likely culprit with my lower-than-normal PSI a failing pump, or should I be looking elsewhere?

Thanks and sorry for the long post! :cool:
 
hmm my first thought would be impeller but sounds like you have done all your homework, it could be a bad bearing which is causing the motor to be louder over work and overheat... its hard to tell without hearing how it sounds. now if your looking to help end its life well that is quite easy just run it dry for a few hours or jam up the impeller and let it run that will end its life quite quickly but could also be dangerous so please be carful
 
If a bearing was bad or going bad, that's going to increase the friction/resistance of the motor's ability to turn the impeller, no? Under "good" conditions (nothing impeding water flow) it seems the pump is moving water adequately, but with the slightest impediment (even a small amount of junk in the pump basket) the pressure in the filter drops off.

I'm trying to correlate the inability to build pressure in the filter and the inability for the pump to overcome even small impediments in the incoming water flow. I want to make sure that the pump is where I should be focused here.

Any other thoughts on what to look at?

I can't imagine there's a blockage in either of the suction lines... there's one from the skimmer and one from the vac port. I would think if there was a blockage in there somewhere it would be more evident?
 
Could very well be a faulty pressure gauge reading low. Check to see if the needle hangs up on its way to zero when you shut the pump off. Being an engineer I'm sure you have a multimeter with a clamp attachment or a clamp meter to read amps, if not shame on you! Bad engineer.... jkjk. Get one and check the amp draw on one of the power wires going to the pump. The rating should be on the motor plate for max rated amps. If you're over that number the pump is more than likely going out and is working too hard.

GL!
 
if not shame on you! Bad engineer....

I'm an engineer, not an electrician! ;)

I don't have clamps, but I can take the cover plate off the panel or the pump and check the amp draw where the wire is exposed.

Even if the pressure gauge is faulty, the fact that it reads a drop in pressure is still relative -- it might not be telling me the correct pressure, but it's telling me that it's losing pressure when even a small amount of debris is in the basket, and I don't think that's normal.
 
Usually, pumps either run or they don't and they really can't slowly die. The reason being is that if the bearings were bad and the load on the motor increased a little, it would run hotter but not much slower. If the load on the motor becomes very large, really bad bearings, the motor will overheat and usually shut down or burn up before it gets much slower. However, there is a little area in between but not much where the motor is near full load but not overloaded such that it will shut down. This could be your case.

But a few questions and observations:

What was the clean filter pressure before all this happened?

Note, that you should clean your filter before the pressure rises more than about 25% or the pump flow rate will start to decrease significantly. One of the bad recommendations by filter manufactures.

Can you post a video with sound of the motor and pump running?
 
This is why I love engineers. When I give a pool school the first question I ask is if anyone is an engineer. You guys make the job so much more interesting with how you make us rise to your level of thinking. Keeps us sharp!

The pressure drop is relative, I was aiming at trying to return to the psi you were familiar with/searching for in case it still was there but just not being displayed right. On to the drop, when you broke the pump apart was the o-ring for the diffuser there? Usually that thing gets stretched out and either falls off upon disassembly or gets eaten up by the impeller. If it's gone that will affect the pressure. Also any sort of air leak will contribute. I've never seen a few leaves have that much of an effect on the filter pressure though but I have seen a few ozone generators opened too much that can drop the psi 5-7 at the filter. Do you have a suction side ozone generator? When you shut the pump off do you see/hear bubbles rising to the top of the lid?
 
Please don't listen to SAC, good lord dude and your a warranty station????

DO NOT RUN YOUR PUMP DRY! I've seen the result of the tremendous heat build-up on the seal that has caught fire and melted/burned down an entire equipment set. Please just let it die of natural causes. The reason all pumps say to not run dry is for this reason. The seal is 2 piece carbon and ceramic and w/o water flowing to maintain the temperature of the seal fire can result. I've spoken to AO Smith directly and they confirm that their motors will run w/o water forever, its the heat from the seal that breaks down the seal and allows water to wick down the shaft and rust out the front bearing thus resulting in motor failure. Just an FYI...
 
The heat could be from the motor going bad or incorrect voltage or a motor that is too small for the impeller.

I would suspect a suction clog is causing the flow issue. Having a suction cleaner feeding directly into a pipe is a bad idea as debris can build up and clog the line.

Get a vacuum gauge and screw it into the front drain plug hole of the pump to see what the suction head is.

Check volts and amp at the motor under load.
 

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What was the clean filter pressure before all this happened?

Clean pressure was always typically about 17-18psi.

Note, that you should clean your filter before the pressure rises more than about 25% or the pump flow rate will start to decrease significantly. One of the bad recommendations by filter manufactures.

Fair enough... my cleaner didn't start to have any issues and flow was still adequate typically up to about 25-26psi. 25% increase over 17 would mean I would be cleaning at 21.25, which would be backwashing every 5-7 days under my typical observed conditions. That seems like a lot.

Can you post a video with sound of the motor and pump running?

I'll take a video this afternoon if I get a chance.
 
You guys make the job so much more interesting with how you make us rise to your level of thinking.

LOL... I've been accused of worse. :cool:

On to the drop, when you broke the pump apart was the o-ring for the diffuser there? Usually that thing gets stretched out and either falls off upon disassembly or gets eaten up by the impeller. If it's gone that will affect the pressure.

Yes... and I took it off, inspected it (it was still pliable, no fraying, and not flattened), put some silicone on it, and reassembled.

Also any sort of air leak will contribute.

Right... I've checked for air leaks a couple times and the couple of pool guys who were out here tested a couple things as well. One of them had me cycle the pump quickly to see if water pushed out of the basket lid. Another one checked the jandy valve to ensure the o-rings in there were good. No air leaks that we can find.

I've never seen a few leaves have that much of an effect on the filter pressure

I wouldn't expect it to, and this is a new/sudden behavior change, so it's certainly anomalous.

Do you have a suction side ozone generator?

Nope, didn't even know such a thing existed. ;)

When you shut the pump off do you see/hear bubbles rising to the top of the lid?

Nope... it's pretty uneventful when the pump shuts off. One time I had a tiny air leak at the basket lid and when I shut it off the water drained out of the pump and it filled with air immediately... but that was a one time thing. I'm careful to make sure the lid is on correctly now considering I have to take it off daily to clean every speck of leaves out of the basket every day now or else I drop to 15...14....13..... :brickwall:
 
The heat could be from the motor going bad or incorrect voltage or a motor that is too small for the impeller.

I know it's not the original motor, but I think it's sized correctly, it's a 1HP/1.65SF which I believe was standard issue for that pump? I think the impeller is either original or OEM equivalent, I'm not sure how to tell. It's got some signs of wear on it so it's been in there for a while.

I would suspect a suction clog is causing the flow issue. Having a suction cleaner feeding directly into a pipe is a bad idea as debris can build up and clog the line.

:scratch:

Where *should* it be plumbed into if not a pipe? I was under the impression that side vac ports were pretty standard, and they typically plumb the way mine does, into a tee with a diverter valve to adjust the suction balance between the skimmer and the vac port.

My main drain is capped off at the skimmer -- not sure if there was a problem in the past with the main drain or if they capped it for some other reason, but I've been told multiple times by multiple people not to worry about it, that I don't need a main drain anyway. So that leaves a single 2" suction run from the skimmer, and a 2" suction run from the vac port, which is a fairly short and straight shot to the equipment pad. They go into a tee with a jandy valve into the pump.

I would think if there was a suction clog in one of the lines, and please, someone correct me if I'm wrong, that it would be pretty evident? Both the skimmer and the vacuum are working, so there's flow through both lines...

Get a vacuum gauge and screw it into the front drain plug hole of the pump to see what the suction head is.

I assume you mean something like this: Amazon.com : 2 Inch Bottom Mount Pool Vacuum Gauge - 0-30 HG : Swimming Pool Filter Valves : Patio, Lawn Garden ?

Will that attach directly to the pump housing or would I need some kind of hose to go between? Seems to me the drain plug hole is pretty close to the ground and clearance to attach the gauge might be inadequate?

Check volts and amp at the motor under load.

Loose electrical service connections are often overlooked when a load is "running hot"

I will check both of these today if time permits. I'll make sure everything is good and secure and put my multimeter on it.
 
The past couple weeks, I've been having issues with pressure being low. My sand filter's pressure can't seem to get above 17-18psi.
Ok, then maybe I misunderstood this statement. Is it running much below that pressure now or are you saying the filter never gets dirty to raise the pressure above that?
 
Ok, then maybe I misunderstood this statement. Is it running much below that pressure now or are you saying the filter never gets dirty to raise the pressure above that?

What I'm saying is that the pressure not only can't/won't rise above that as the filter gets dirty, but that I LOSE pressure very easily with even the smallest amount of debris in the pump basket.

I backwashed a couple days ago, and the water was plenty dirty... but my pre and post backwash pressure was the same. I was about 17 before I backwashed (and it had been about 4 weeks) and I was at 17 after I backwashed, which is close to my normal clean pressure.

After 4 weeks I should have been near 30.
 
Sounds like a bad pressure gauge to me. If the filter gets dirty the pressure should increase at the gauge and the flow will decrease.

Does the gauge go to zero when the pump is shut off?
 
If the filter gets dirty the pressure should increase at the gauge and the flow will decrease.

I understand that's what *should* happen... and usually it is what happens. However, right now, it's not happening. Thus my conclusion that something is amiss.

Does the gauge go to zero when the pump is shut off?

Yes it does. It drops to zero without hanging up, and it goes up to pressure when the pump is on smoothly and without hanging up. 2 pool pros have both told me the pressure gauge appears to be working fine.

I'm sure they could be wrong, but that still doesn't explain why the pump/filter loses pressure so easily when there's anything in the basket. I've been gone for 2-3 day weekends and come back to skimmer and pump basket that are both pretty full of junk, and yet the pump/filter maintained pressure well over 20-22psi and there was plenty of flow. I never had enough crud in either basket to clog it up so bad that water couldn't flow, even after 3-4 days of being away. The behavior now is that even a small amount of junk in the basket makes the pressure drop fairly rapidly. If I let it go for 2-3 days now I could imagine I'd be down to 8 or 10psi pretty quickly. I have to clean both skimmer and pump baskets daily and 100%, can't leave even a trace of crud in there.
 
You keep saying the pressure goes down but to me that means the pressure at the filter gauge is going down but you said before that is the same so I am confused by your terminology.

By pressure are you talking about the pressure coming out of the returns?

If flow rate is changing the pressure at the pressure gauge must change.
 
You keep saying the pressure goes down but to me that means the pressure at the filter gauge is going down but you said before that is the same so I am confused by your terminology.

By pressure are you talking about the pressure coming out of the returns?

If flow rate is changing the pressure at the pressure gauge must change.

The pressure at the filter, on the gauge.

What is the same is the clean pressure. 17-18. That's my usual and consistent clean pressure.

My DIRTY pressure, however, is now the same as my clean pressure -- meaning that instead of the pressure inching up from 17/18 to 25/26 over the course of a couple weeks, the pressure NEVER increases beyond 17-18 and in fact DECREASES if there's any debris at all in the pump basket. Even with a perfectly clean basket, the pressure hovers at 17-18 and never gets any higher. A little bit of crud in the pump basket and it will easily drop to 16, 15, or lower. I used to hit 25-26 every 2 weeks consistently, and then I would backwash. I let it go 4 weeks this time and it was still 17. I backwashed (and the water was pretty dirty indicating a dirty filter) and after back washing the pressure was STILL 17.

It just seems like whether the filter is freshly cleaned or 4 weeks dirty, the pump cannot push more than 17-18 psi at best anymore.
 
in fact DECREASES if there's any debris at all in the pump basket.
That is normal. More suction head reduces flow rate which in turn reduces filter pressure. Nothing surprising there.


I used to hit 25-26 every 2 weeks consistently, and then I would backwash. I let it go 4 weeks this time and it was still 17. I backwashed (and the water was pretty dirty indicating a dirty filter) and after back washing the pressure was STILL 17.
There could be several reasons for that. Previously, if you were fighting an algae bloom, it would quickly clog a filter causing a rapid rise in filter pressure. If now, you no longer have any algae, the filter pressure would take much much longer to rise. But if the filter is indeed getting dirty and clogging the filter, then again, it has to be the filter gauge.


It just seems like whether the filter is freshly cleaned or 4 weeks dirty, the pump cannot push more than 17-18 psi at best anymore
Remember that high pressure is an indication of high head loss. Not really a good thing. If your filter gauge is working properly, you should be celebrating, not worrying.

But as a reminder, if the flow rate is decreasing and there is NO change in filter pressure, the gauge is bad.
 

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